3 [![Coverity Scan Build Status][17]][18]
5 ***WARNING: This project has moved to [https://git.yzena.com/][20] for [these
6 reasons][21], though GitHub will remain a mirror.***
8 This is an implementation of the [POSIX `bc` calculator][12] that implements
9 [GNU `bc`][1] extensions, as well as the period (`.`) extension for the BSD
12 For more information, see this `bc`'s full manual.
14 This `bc` also includes an implementation of `dc` in the same binary, accessible
15 via a symbolic link, which implements all FreeBSD and GNU extensions. (If a
16 standalone `dc` binary is desired, `bc` can be copied and renamed to `dc`.) The
17 `!` command is omitted; I believe this poses security concerns and that such
18 functionality is unnecessary.
20 For more information, see the `dc`'s full manual.
22 This `bc` is Free and Open Source Software (FOSS). It is offered under the BSD
23 2-clause License. Full license text may be found in the [`LICENSE.md`][4] file.
27 This `bc` only requires a C99-compatible compiler and a (mostly) POSIX
28 2008-compatible system with the XSI (X/Open System Interfaces) option group.
30 Since POSIX 2008 with XSI requires the existence of a C99 compiler as `c99`, any
31 POSIX and XSI-compatible system will have everything needed.
33 Systems that are known to work:
40 * Solaris* (as long as the Solaris version supports POSIX 2008)
43 Please submit bug reports if this `bc` does not build out of the box on any
44 system besides Windows. If Windows binaries are needed, they can be found at
49 This `bc` should build unmodified on any POSIX-compliant system.
51 For more complex build requirements than the ones below, see the
54 ### Pre-built Binaries
56 It is possible to download pre-compiled binaries for a wide list of platforms,
57 including Linux- and Windows-based systems, from [xstatic][6]. This link always
58 points to the latest release of `bc`.
62 For the default build with optimization, use the following commands in the root
72 To only build `bc`, use the following commands:
75 ./configure.sh --disable-dc
79 To only build `dc`, use the following commands:
82 ./configure.sh --disable-bc
88 For debug builds, use the following commands in the root directory:
97 To install, use the following command:
103 By default, `bc` and `dc` will be installed in `/usr/local`. For installing in
104 other locations, use the `PREFIX` environment variable when running
105 `configure.sh` or pass the `--prefix=<prefix>` option to `configure.sh`. See the
106 [build manual][5], or run `./configure.sh --help`, for more details.
110 This `bc` does provide a way to build a math library with C bindings. This is
111 done by the `-a` or `--library` options to `configure.sh`:
117 When building the library, the executables are not built. For more information,
118 see the [build manual][5].
120 The library API can be found in [`manuals/bcl.3.md`][26] or `man bcl` once the
121 library is installed.
123 The library is built as `bin/libbcl.a`.
125 ### Package and Distro Maintainers
127 #### Recommended Compiler
129 When I ran benchmarks with my `bc` compiled under `clang`, it performed much
130 better than when compiled under `gcc`. I recommend compiling this `bc` with
133 I also recommend building this `bc` with C11 if you can because `bc` will detect
134 a C11 compiler and add `_Noreturn` to any relevant function(s).
136 #### Recommended Optimizations
138 I wrote this `bc` with Separation of Concerns, which means that there are many
139 small functions that could be inlined. However, they are often called across
140 file boundaries, and the default optimizer can only look at the current file,
141 which means that they are not inlined.
143 Thus, because of the way this `bc` is built, it will automatically be slower
144 than other `bc` implementations when running scripts with no math. (My `bc`'s
145 math is *much* faster, so any non-trivial script should run faster in my `bc`.)
147 Some, or all, of the difference can be made up with the right optimizations. The
148 optimizations I recommend are:
151 2. `-flto` (link-time optimization)
155 Link-time optimization, in particular, speeds up the `bc` a lot. This is because
156 when link-time optimization is turned on, the optimizer can look across files
157 and inline *much* more heavily.
159 However, I recommend ***NOT*** using `-march=native`. Doing so will reduce this
160 `bc`'s performance, at least when building with link-time optimization. See the
161 [benchmarks][19] for more details.
163 #### Stripping Binaries
165 By default, non-debug binaries are stripped, but stripping can be disabled with
166 the `-T` option to `configure.sh`.
168 #### Using This `bc` as an Alternative
170 If this `bc` is packaged as an alternative to an already existing `bc` package,
171 it is possible to rename it in the build to prevent name collision. To prepend
172 to the name, just run the following:
175 EXECPREFIX=<some_prefix> ./configure.sh
178 To append to the name, just run the following:
181 EXECSUFFIX=<some_suffix> ./configure.sh
184 If a package maintainer wishes to add both a prefix and a suffix, that is
187 **Note**: The suggested name (and package name) when `bc` is not available is
190 #### Karatsuba Number
192 Package and distro maintainers have one tool at their disposal to build this
193 `bc` in the optimal configuration: `karatsuba.py`.
195 This script is not a compile-time or runtime prerequisite; it is for package and
196 distro maintainers to run once when a package is being created. It finds the
197 optimal Karatsuba number (see the [algorithms manual][7] for more information)
198 for the machine that it is running on.
200 The easiest way to run this script is with `make karatsuba`.
202 If desired, maintainers can also skip running this script because there is a
203 sane default for the Karatsuba number.
209 It is well-tested, fuzzed, and fully standards-compliant (though not certified)
210 with POSIX `bc`. The math has been tested with 40+ million random problems, so
211 it is as correct as I can make it.
213 This `bc` can be used as a drop-in replacement for any existing `bc`. This `bc`
214 is also compatible with MinGW toolchains, though history is not supported on
217 In addition, this `bc` is considered complete; i.e., there will be no more
218 releases with additional features. However, it *is* actively maintained, so if
219 any bugs are found, they will be fixed in new releases. Also, additional
220 translations will also be added as they are provided.
222 ## Comparison to GNU `bc`
224 This `bc` compares favorably to GNU `bc`.
226 * It has more extensions, which make this `bc` more useful for scripting.
227 * This `bc` is a bit more POSIX compliant.
228 * It has a much less buggy parser. The GNU `bc` will give parse errors for what
229 is actually valid `bc` code, or should be. For example, putting an `else` on
230 a new line after a brace can cause GNU `bc` to give a parse error.
231 * This `bc` has fewer crashes.
232 * GNU `bc` calculates the wrong number of significant digits for `length(x)`.
233 * GNU `bc` will sometimes print numbers incorrectly. For example, when running
234 it on the file `tests/bc/power.txt` in this repo, GNU `bc` gets all the right
235 answers, but it fails to wrap the numbers at the proper place when outputting
237 * This `bc` is faster. (See [Performance](#performance).)
241 Because this `bc` packs more than `1` decimal digit per hardware integer, this
242 `bc` is faster than GNU `bc` and can be *much* faster. Full benchmarks can be
243 found at [manuals/benchmarks.md][19].
245 There is one instance where this `bc` is slower: if scripts are light on math.
246 This is because this `bc`'s intepreter is slightly slower than GNU `bc`, but
247 that is because it is more robust. See the [benchmarks][19].
251 To see what algorithms this `bc` uses, see the [algorithms manual][7].
255 Currently, this `bc` only has support for English (and US English), French,
256 German, Portuguese, Dutch, Polish, Russian, Japanese, and Chinese locales.
257 Patches are welcome for translations; use the existing `*.msg` files in
258 `locales/` as a starting point.
260 In addition, patches for improvements are welcome; the last two messages in
261 Portuguese were made with Google Translate, and the Dutch, Polish, Russian,
262 Japanese, and Chinese locales were all generated with [DeepL][22].
264 The message files provided assume that locales apply to all regions where a
265 language is used, but this might not be true for, e.g., `fr_CA` and `fr_CH`.
266 Any corrections or a confirmation that the current texts are acceptable for
267 those regions would be appreciated, too.
271 Other projects based on this bc are:
273 * [busybox `bc`][8]. The busybox maintainers have made their own changes, so any
274 bugs in the busybox `bc` should be reported to them.
276 * [toybox `bc`][9]. The maintainer has also made his own changes, so bugs in the
277 toybox `bc` should be reported there.
279 * [FreeBSD `bc`][23]. While the `bc` in FreeBSD is kept up-to-date, it is better
280 to [report bugs there][24], as well as [submit patches][25], and the
281 maintainers of the package will contact me if necessary.
285 This `bc` is written in pure ISO C99, using POSIX 2008 APIs.
289 This `bc` uses the commit message guidelines laid out in [this blog post][10].
291 ## Semantic Versioning
293 This `bc` uses [semantic versioning][11].
297 Items labeled with `(maintainer use only)` are not included in release source
302 .gitignore The git ignore file (maintainer use only).
303 configure A symlink to configure.sh to make packaging easier.
304 configure.sh The configure script.
305 functions.sh A script with functions used by other scripts.
306 install.sh Install script.
307 karatsuba.py Script to find the optimal Karatsuba number.
308 LICENSE.md A Markdown form of the BSD 2-clause License.
309 link.sh A script to link dc to bc.
310 locale_install.sh A script to install locales, if desired.
311 locale_uninstall.sh A script to uninstall locales.
312 Makefile.in The Makefile template.
313 manpage.sh Script to generate man pages from markdown files.
314 NOTICE.md List of contributors and copyright owners.
315 RELEASE.md A checklist for making a release (maintainer use only).
316 release.sh A script to test for release (maintainer use only).
317 safe-install.sh Safe install script from musl libc.
321 gen The bc math library, help texts, and code to generate C source.
322 include All header files.
323 locales Locale files, in .msg format. Patches welcome for translations.
324 manuals Manuals for both programs.
328 [1]: https://www.gnu.org/software/bc/
330 [5]: ./manuals/build.md
331 [6]: https://pkg.musl.cc/bc/
332 [7]: ./manuals/algorithms.md
333 [8]: https://git.busybox.net/busybox/tree/miscutils/bc.c
334 [9]: https://github.com/landley/toybox/blob/master/toys/pending/bc.c
335 [10]: http://tbaggery.com/2008/04/19/a-note-about-git-commit-messages.html
336 [11]: http://semver.org/
337 [12]: https://pubs.opengroup.org/onlinepubs/9699919799/utilities/bc.html
338 [17]: https://img.shields.io/coverity/scan/16609.svg
339 [18]: https://scan.coverity.com/projects/gavinhoward-bc
340 [19]: ./manuals/benchmarks.md
341 [20]: https://git.yzena.com/gavin/bc
342 [21]: https://gavinhoward.com/2020/04/i-am-moving-away-from-github/
343 [22]: https://www.deepl.com/translator
344 [23]: https://svnweb.freebsd.org/base/head/contrib/bc/
345 [24]: https://bugs.freebsd.org/
346 [25]: https://reviews.freebsd.org/
347 [26]: ./manuals/bcl.3.md